Is a half day of heat too long to pull eggs to collect for a broody?

We've decided to do our first batch the natural way and have a BO that is clearly broody. We want to pick certain eggs for her to set from 3-4 days worth from our 15 hens. I've read that we should keep them at room temp and tilt them twice a day until we have the full batch ready. However, she's been sitting on almost everyone's eggs (9) since this morning, and we just now pulled them (4:30 pm). Is it too late to use these? Does 4-8 hours of heat start the embryo development going, and cause trouble if we pull them out of the heat now?

I don't know if those few hours will make a difference or not. Personally, I'd just let her hatch out the nine eggs. I don't know how many you were planning on giving her, but you don't want to give her so many that she can't adequately cover them all, either. I had a broody BO last fall that had 13 eggs. That was a pretty good-sized clutch for her. (Unfortunately I tried moving her and the nest and it didn't end well, but I did notice that most of the eggs had started to develop.) Good luck!

Thanks! It's not that we want more than 9, in fact, that's probably about the right number. The issue is which 9 (or 10). We're looking for some interesting color combinations. Our roo is a Welsummer, and we have BOs, RIRs, EEs, a Dom and a Wellie hen. We figure it'll take about 3 days to get 9 or 10 of the right ones.